99 civic ex with jdm sohc zc non vtec ..problems!!



#1
Hey guys new to this site and threads. Well i have a 99 civic ex ((originally vtec)) with a jdm d16zc sohc non vtec motor and ex 5spd tranny and is giving me a couple of problems. First off everytime i start my car up it idles so low that the car would want to die and transmission shifts very rough and jerky. My car sputters all the time like it has two step or something.

All the wiring was done correctly and correct ecu is being used. What strange is that when i run the original ecu the car drives perfect and shifts smoothely only problem it has is an idling problem where rpms go up and down and wont pass 5500 rpm because i have no vtec obviousl y and using the vtec ecu.But when i run the non vtec ecu which would b a 99 -00 civic p2e i get all these problems listed in the first paragraph.

Do i have to change my engine harness to non vtec or is it a more serious problem.any help would b greatly appreciated!

Motor is a 96-99 jdm zc sohc non vtec obd2
 


#2
Shouldn't have to change your harness. I'd believe that if the plug isn't needed by the ECU, it won't care if it's there or not, UNLESS it's running to a different input.

On another note, you could also get a vtec head for that engine if it's available to do (someone help me out here)

Automatic or manual tranny? Does it shift rough and jerky with the vtec ecu in it?
 

speedygonzales

Royal Member ~ RonJ
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#3
oh boy... you are using the wrong ecu... the d16zc is either obd1 or obd0... get the right ecu and a jumper harness and it should fix your problem

edit: ok so I was dead tired when I wrote that and didn't look around enough... my bad
 


#4
Its a manual transmission. It only shifts rough and jerky with the non vtec ecu plus extremely low idle on start up. When i use the vtec ecu it engages gears very smoothely and doesnt sputter unlike the non vtec ecu. Definetly planning on getting the vtec head soon . Im.just going to run the setup i have now for a while. Dont know if im using the wrong ecu even though i did tons of research and it tells me to use the p2e
 
#6
The engine is OBD-1

Also, The non-VTEC SOHC ZC is similar to the D16A6 ('91–'96) and D16Y4 ('96–2000) engine, but with more aggressive cam timing.

You should be using a P91 ECU.
 
#7
I cant use a p91 because its a jdm vtec ecu for the d16a. I need the non vtec ecu. But im still not sure if the ecu is the problem. Probably is but not sure. Dont know what to do about this problem.its so annoying. Im going to try to do the obd2 to obd1 conversion. Im using the y8 distributer and intake manifold is that ok??
 

speedygonzales

Royal Member ~ RonJ
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#9
Im using the y8 distributer
that could be one of the problems, because its ment for a vtec engine. swap that out and try a non vtec distributor. also if its non vtec then you NEED a non vtec ecu
 
#10
Just found out i have a huge intake manifold leak. I sprayed some starting fluid around the intake manifold where it connects to the head and car shut right off..and its also very noticiable to hear the leak. Can this contribute to all the symptoms i been having?
 

speedygonzales

Royal Member ~ RonJ
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5+ Year Member
#11
Just found out i have a huge intake manifold leak. I sprayed some starting fluid around the intake manifold where it connects to the head and car shut right off..and its also very noticiable to hear the leak. Can this contribute to all the symptoms i been having?
I don't think this has anything to do with the way your engine is running. now if it were an exhaust manifold leak then you could start looking into it but naw the leak shouldn't be causing the problem
 
#12
Im definetly going to look into that. I did put after market headers on but i dont notice a leak from it..my next approach to solve this problem would b to do a obd2b to obd1 harness conversion with an obd1 ecu. Hopefully that solves my problem if not im just getting rid of the car as nice as it is.
 

jlicrx

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#13
OBD2 SOHC ZC non-VTEC should run fine with Y8 distributor and P2E ECU - maybe the ECU is bad?

any codes showing at the ECU?
 

jlicrx

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#14
When i brought the motor the guy told me it was obd2 . Paperwork says 96-99 sohc zc obd2.maybe he is wrong?
this is the OBD2 SOHC ZC non-VTEC - does yours look like this? - the dipstick is the main clue - only OBD2 has dipstick in this location





 
#15
Yess that is the same exact motor i have in my car! Now at first i thought i had a bad ecu and picked up another p2e but it still runs the same. That motor in the pics is obd2 but others say its obd1. I noticed today when i unplugged my iacv sensor there was no change in my crappy idle. I tried plugging it back in again and still no change. Does that mean my iacv isnt working??

I still have to check for codes . It runs like crap so i do have a cel on. Will post it as soon as i get the readings.
 
#18
Definetly runs better with the vtec ecu. Im just on a tight budget and want to get this motor to run right. And thanks jlicrx for providing these pics. The whole swap was done correctly . All sensors except vtec and the ckf ( crank fluctuation sensor) were hooked up. Providing that jdm engines dont use a ckf sensor. I just dont know what else to do.. As i said idle at start up is extremely low, car sputters all the time and lacks power. I put all new spark plugs , wires, fuel filter, and rotor. As i said beofre the iacv senor doesmt make a difference to the car weather its hooked up or not..dont know if this is the cause of all the problems.
 
#19
OBD2 SOHC ZC non-VTEC should run fine with Y8 distributor and P2E ECU - maybe the ECU is bad?

any codes showing at the ECU?
Just got the codes diagnosed. my car is reading
P1519 (IDLE AIR CONTROL VALVE CIRCUIT)
P1300( MULTIPLE CYLINDER MISFIRE DETECTED)

i knew for sure i had a problem with my iac valve. i used the whole y8 manifold and throttle body along with the iac valve and slapped it on the zc head and was a perfect fit. Now the issue here is that i dont think any signal is going to the iac valve because if i unplug it nothing changes as far as engine idle or performance, its still crappy. Does this need to be replaced or do i have a wiring issue? any help would be very great =)
 
#20
89-91 zc

what did you do cuz i have same problems...... but im using a 89-91 sohc zc motor and 99 y8 intake

:roll::roll:
 






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